it into that class. In doubtful cases the catalogs of other libraries
are often good guides.

Keep your classification as consistent as possible. Before putting a
book, about which there is any opportunity for choice, in the class
you have selected for it, examine your shelf-list and see that the
books already there are of like nature with it.

Classify as well as you can, and don't worry if you find you have made
errors. There are always errors. Don't get into the habit of changing.
Be consistent in classifying, and stick by what you have done.




CHAPTER XXI

The Dewey or Decimal system of classification

[From the Introduction to the Decimal classification and Relative
index. Published by the Library Bureau, $5.]


The field of knowledge is divided into nine main classes, and these
are numbered by the digits 1 to 9. Cyclopedias, periodicals, etc.,
so general in character as to belong to no one of these classes,
are marked nought, and form a tenth class. Each class is similarly
separated into nine divisions, general works belonging to no division
having nought in place of the division number. Divisions are similarly
divided into nine sections, and the process is repeated as often